1. Field of the Invention
The present invention relates to a humidity-sensitive actuator, and more particularly to a humidity-sensitive actuator made of piezoelectric electrostrictive ceramic and capable of both detecting the humidity of a surrounding environment and producing a flexural deformation in response to the detected humidity.
2. Description of the Prior Art
Heretofore, humidity control apparatus such as airconditioning units, measuring instruments or the like have had a number of humidity sensors and a number of actuators separate from the humidity sensors and controllable in response to signals from the humidity sensors.
However, conventional humidity control apparatus have disadvantages because the wires and cables electrically connecting those humidity sensors and actuators to the control unit are highly complex, whereby the humidity control apparatus cannot easily be manufactured, inspected and repaired.
Among the prior art attempts to solve these problems, Japanese laid-open patent publication No. 1-109782 published Apr. 26, 1989 discloses a monomorph actuator comprising a piezoelectric element which produces a flexural displacement depending on the voltage applied thereto. Japanese laid-open patent publication No. 64-84762 published Mar. 30, 1989 shows a bimorph piezoelectric device composed of two piezoelectric elements joined to each other through a conductive leaf spring interposed therebetween and the bimorph piezoelectric device is flexed when a voltage is applied thereacross between the piezoelectric elements.
However, nothing in these publications shows or suggests a humidity-sensitive actuator which produces a flexural displacement depending on the humidity of a surrounding environment while a voltage is being applied across the humidity-sensitive actuator.